The Heart of an Induction Heater

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Heart of an Induction Heater
Hello everyone! I started this morning out with a beautiful walk along the gulf coast for the American Heart Association. I wanted to share two things with you today, a couple photos from the event and one more thing (keep reading).
Gulf Coast Heart Walk American Heart Association American Heart Association Heart Walk American Heart Association

Generosity Begets Generosity

All the giving got me thinking, after all, you know what they say about giving. Generosity Begets Generosity. Generosity is a gift that keeps on giving—so many of the gifts we receive in life turn us into givers.
I wanted to show my appreciation to the Patrons who continue to believe in this project even when life slows its progress way more than I’d like! I was reminded today that I actually did not start this project for myself. I am not a blacksmith, I have no immediate need for an induction heater, but I am a creator. Each and every human has this incredible capacity to imagine and to change things. I wanted to bring a tool within the reach of others that remained out of reach for most. Not a wimpy, “doesn’t deliver on what the box said kind of tool”, but one of a caliber that is not matched in the consumer market at all today.

The Heart of an Induction Heater

I would like to offer the “heart of an induction heater” to all of my existing Patrons (as of today September 22, 2018).
U-I Core Set
E/I Core from two U/I cores
U-I Core Set
At about twice the size of a human heart and just about as difficult to source, the matching transformer is by far the most critical, specialized component of the induction heater. Coolant flows around its core in two directions keeping it cool as huge amounts of energy flow through it, making it possible to pump power from your wall outlet into your workpiece. Without it, the IH is just an inverter with some other not really all that exciting electronics. It would be akin to a truck without a transmission. You can’t just connect the crankshaft to the wheels and expect anything good!
I’m including two massive U & I core sets. The same ones that make up the large E/I matching transformer in the newest revision.
Material: 3C85
  • Single U-I core set AL: ~8400
  • Single U-I core set µe: ~2000
  • Single U-Core Dimensions: 93mm x 76mm x  30mm thick
  • Single I-Core Dimensions: 93mm x 28mm x 30mm thick
  • Overall Dimensions: U-I Set: 104mm x 93mm
  • Opening Dimensions: 47mm x 36mm
3C85 Material Technical Data:
  • Optimal frequency: < 200kHz
  • Permeability ui:           2000 +/- 20%
  • Induction at 100kHz, 250 A/m, Bs:   > 400mT
Heart of an Induction Heater

But Wait There’s More

Since driving your IGBT properly is a big deal and kind of important for the whole setup, I’m also including a new driver PCB with two Powerex VLA504-01 Hybrid IC Gate Drivers and two Powerex VLA106-15242 DC to DC Converters. Just those four components are about a $70 value alone if you buy them from Digi-Key. The remaining components on the board are just a few dollars worth of passives. an entire Hybrid Driver kit! The full schematics and bill of materials for the Hybrid Driver board can be found here:
For more info on the driver board be sure to read this:
As well as this post:
Recap, what I’m giving my Patrons:
  • 2 x 93mm x 76mm x  30mm 3C85 Ferrite U Cores
  • 2 x 93mm x 28mm x 30mm 3C85 Ferrite I Cores
  • 1 x New Hybrid Driver Kit including all parts in the BOM above and a PCB

That is a $106.85 value. Thank you for your support!

If you would like to purchase an additional driver kit or U/I core set I’ve included info on that in the FAQs below.

Send Me Free Stuff!

If you are currently a Patron as of the date of this post and would like me to send you this thank you gift, just drop me a private message on Patron saying hello and include your shipping address. The only thing I would ask is that you only request this gift if you are going to use it. We’ll go on the honor system here. 🙂
I look forward to working on this project more and hearing your feedback as well, as you either work on your own or use an IH I’ve built for you in the future.
Q: Is it possible to drive a tank circuit in an Induction Heater with one IGBT?
A: Yes.  This is actually how my brothers old IH is set up now. Here is a quick schematic. The capacitors were all off eBay for cheap.
Single IGBT Inverter
Matching transformer and coupling caps
Single IGBT Inverter
Filter Cap & Coupling Caps
Single IGBT Inverter
Single IGBT driver and brick
Single IGBT Inverter Schematic
Single IGBT inverter schematic
Q: Can you share more details on the matching transformer?
A: Of course but I need some more space to do it properly. I’m working on a post about just that. In the meantime here is a photo and a short explanation to give you something to start with.
  • The Matching transformer is wound with 1/4″OD inch copper tubing.
  • All windings are wrapped in x2 overlapping Scotch Professional Grade Vinyl Electrical Tape Super 88. Meaning as you spiral down the length of the copper tube the electrical tape covers 50% of the layer before it resulting in a 50%+50% overlap (no gaps) and a 200% layer thickness overall (better electrical and mechanical isolation).
  • The primary winding (connected to the inverter) is composed of 13-14 turns. It has terminals made of copper soldered near the ends to accommodate a high current connection while leaving the ends of the tube free to hook up to the cooling system.
  • The secondary winding (connected to the tank cap and work coil) is a single turn composed of 4 individual 1/4″ copper tubes connected on each end with a 1/2″ manifold. One side of the manifold connects to one side of the tank capacitor, the other connects to one side of the work coil via a copper plate. The other side of the work coil connects back to the other side of the tank capacitor via another copper plate in close proximity to the first plate. This whole set up ensure the flux is fully enclosed in the system. Were it not you would heat up surrounding metal and loose usable power. (An issue in the first model with the toroidal matching transformer and large tank setup.)
Matching Transformer
Q: If I’m not currently a Patron or I would like an additional hybrid driver kit could I just purchase one?
A: Yes. I’m not set up to do this formally yet but I can accept Paypal, just drop me a message. For this small batch I made, I’m selling them for $54.95 flat (free shipping to the 48 states, at cost everywhere else). That’s half the cost of buying all the parts yourself or a similar evaluation board (the BG2B). I’ll be able to get this even lower in the future on larger orders for inclusion in the full IH kit. Done! –> I’m also still working on a bulk order for the passives to get the entire driver kit complete. The price difference with and without the passives will likely be less than a couple bucks, keep that in mind if ordering those parts would be an issue for you.
Here is the full excel pricing sheet with individual component pricing info from Digi-Key current as the date of this post.
Q: If I’m not currently a Patron or I would like an additional set of ferrite U/I cores could I just purchase one?
A: Yes. These are quite heavy and require careful packing since they are a fragile ceramic. I’m selling them for $25.95 a set (1 x U core and 1 x I core) flat (free shipping to the 48 states, at cost everywhere else).
Q: What shipping method are you using for the free shipping option?
A: Whichever is the lowest cost at the time of shipping to your location. Usually either USPS first class, priority, or FedEx ground. If you would like to choose a specific method I can do that and just pass on the exact cost to you, no markup.
Q: What about the other parts of the system like the main board, AC rectification & filtering, liquid cooling setup, etc. Can I get one of those?
A: Although I do have fairly complete designs worked out on the rest of the system I don’t have a stock on the parts. I am going to start making posts on the individual components starting with the matching transformer to give you what you need to duplicate each part. The main board schematic and board design are on GitHub although I will be making some changes to it on the next go around.

Happy March!

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Jeremiah's Knives
Good morning and can you believe it’s March already? Wow! Now that Chinese New Year is past the last of the packaging materials for the IGBT Hybrid Driver kits have shipped. I’m now looking forward to getting it all packaged up. I have some fun and unique ideas for the packaging as well. 🙂
Between ice and snow days, three kids with the flu, then me with it for a couple of days and throw some travel in there I’ve been working on the guide for the kit a bit more. It is coming together beautifully, and I enjoy working on it. But to be honest, I’m most excited to get back to work on finishing the main code. However since the drivers are a crucial part of the overall kit, this is time well spent.

Forging Ahead

On another note, while my brother Daniel is in the process of moving I let a friend, Jeremiah borrow the original induction heater. Jeremiah has been making knives for the better part of last year using stock blanks and handcrafting the handles from various materials. He wanted to get his feet wet forging his own blades from scratch but doesn’t have the area or set up for a flame forge. Maybe we’ll get some nice pictures or even a video or three. He is new to forging but has been studying the last few months, so he was ready for the IH!
Here is some of Jeremiah’s recent work. I believe he said these were Christmas presents this past year. 
 Jeremiah's Knives
I’ve met others with impressive talents in blade crafting like Larry Fahnoe, check out his creations too! I am truly excited to see more people with access to induction heating and what they’ll do with it.

Driver Kit Update & $400 AA Battery Accident

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Broken MacBook Pro LCD

Driver Kit Update

It’s been a busy couple of weeks, both with my day job and working with suppliers to get the best price and quality on parts for the hybrid driver but I do have a driver kit update. I have finalized the supply chain and received all but the passive components and packaging materials. I expect everything to be here by the end of January. Once I have all the parts I’ll take the photographs for the plans, which will be available for free.
I also want to make a test rig for the hybrid driver ICs and the isolated DC to DC converters. They are critical components and cost a decent amount. I want to know that they are performing as expected before they go out in the kits or machines. I have a couple of ideas for building a simple but detailed and accurate Arduino based performance curve profiler similar to those used for testing transistors, diodes, and other electronic components. In the meantime, I’m getting back into the code using the two new driver boards I build from the spare components.
 

$400 AA Battery Accident

I dropped a harmless little AA on my desk while changing the batteries in my mouse. The battery bounced and rolled away, I didn’t think much about it. A few minutes later I noticed my screen took a hit… awesome. The outer glass isn’t even cracked. It was one of the substrate layers that broke and let out all the magic liquid crystals. Looking around for a replacement LCD for my MacBook Pro Retina, 15-inch, Mid 2014 it seems like $300-$390 is the price range, ouch! I saw some cheaper off brands but this is a beautiful Retina display, and I don’t want to change it out for some knockoff junk LCD.
I have been looking at the new MacBook Pros, but I genuinely don’t like them. The taskbar is a POS gimmick, and the keyboard feels like a toy. I switched to using MacBooks around 2009 when I got fed up with Windows interfering with my work. An [NTFS file system error] blue screen of death the night of a large network activation for AT&T Lightspeed/U-verse was the last straw. I went out and bought my first Mac the next day.
Yes, Mac hardware is costly, but it JUST WORKS! It is always something with Windows. I was tired losing valuable time fixing issues, updating, reinstalling, etc. The MacBooks I have used have ALWAYS worked rock solid. I run CleanMyMac to keep things tidy and a Time Machine at home which is the most intuitive and real world usable backup system ever, for a personal computer at least.
I didn’t mean for this to be a MacBook fanboy review or a windows roasting session, I still use windows too. Personal my favorite OS is Debian, maybe I’ll get a Linux computer. Probably not though, I just run VMware when I need it locally. Besides, I do love the integration between all my devices that Apple affords i.e., desktop, laptop, tablet, phone, TV, etc… It’s just that this is the first physical problem I’ve ever had with a Mac and honestly I’m sort of surprised how easy it broke considering how rough I’ve been on them over the years.
I’m going to order a screen today. I just tell myself, “Don’t worry, you can sell this Mac for about a grand when you upgrade!” Still, what a disappointing accident.

IGBT Driver – Out With The Old, In With The New (Year)

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IGBT Driver PCB

First off, happy New Year! I hope that everyone is doing well in 2018. The first batch of IGBT Driver boards (Hybrid Driver v1.3) from PCBWay came in today, and they look great! 🙂

IGBT Driver Old And New - PCBWay

PCBWay Manufacturer

This order was my first time using PCBWay and I am blown away by how seamless from end to end the entire process is! I love the technological process tracking, it’s funny, but it reminds me a bit of how some pizza places track the progress of your pizza. My order was accepted, manufactured, shipped and in my shop in no time at all!

The quality of the boards, through-hole plating, silkscreen, bottom side tinning, and everything is a definite A+. I received excellent communication and engineering cooperation from the beginning. Although there are other PCB manufacturers that I like, I am going to use these guys going forward! I’d recommend them for prototyping or production.

PCBWay Technological Process Tracking

Open Source Advocate

I especially like that they encourage open source projects by allowing you to share your board designs, schematics, and project details after ordering. Here is the Hybrid Driver v1.3 in PCBWay’s project sharing section.  They make it easy for others to order boards since all the Gerber files are already there and pre-approved. They even give a 10% back to the project creator. Check it out and take a look at there projects, there are some impressive ones. I like OpenReflow, a control board to convert a simple toaster oven into an accurate reflow oven for soldering SMD components.

IGBT Driver

The new driver boards look great. I like the high gloss black solder mask and the highly visible white silkscreen over it. The slots for the IGBT gate connections turned out great. The board edges are clean and completely burr free. The only mistake I’ve found is that I forgot to set the OSH logo font to vector, so it expanded a bit and overlapped the G2 silkscreen. I also tweaked a few device name silkscreen positions to improve visibility.

IGBT Hybrid Driver v1.3

I’m waiting for the bulk orders of the VLA106-15242 isolated DC to DC converters and the M57962L gate drivers. After that, I’ll stuff the boards and get them in the ReactorForge to continue refining the firmware.


IGBT Driver Stuff Board

The First Kit

I’m planning on making the IGBT Driver (Hybrid Driver v1.3) the first complete kit. Of course, it will be standalone, apart from the rest of the induction heater. I’m ok with having the major components of the induction heater available individually as well as part of the whole machine kit.

I have never made a kit like this, but I am entirely confident that I can put together a great one. Still, this will give me the chance to test that confidence on a smaller scale. I’ve already established a supply chain for the parts and the PCB. What’s left is ordering consumables such as antistatic shielding bags, labels, and packaging. Then, of course, the written plans or instructions for the kit.

Patreon Charges and 260 Pound Parts Delivery for IH Kit

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Patreon Charges

There has been a lot of confusion created by they way Patreon charges its patrons and paying creators. You can find the official information can here: https://patreon.zendesk.com/hc/en-us/articles/115005631963 And here is another excellent article on the topic by TechCrunch.

TLDR; The short version is, Patreon moved its credit card processing service fees from the creator to the patron. Because of this change, Patreon was able to lower the overall fee amount and give more to the creator. The fee amount is (2.9% + $0.35) for each monthly pledge.

Because I have worked on unique e-commerce projects, I understand the intricacies and complications of bulk credit card processing, multiple payees, and the associated charges and chargeback liabilities. However, I do not support Patreon’s decision, and I firmly believe there is a better solution. Because Patreon is a goodwill engine, I think this move is, for lack of better terms, just weird. In addition, I won’t personally be canceling any of my Patreon pledges. Nevertheless, as a patron myself and now a fledgling creator, I do hope that we see these processing fees moved back to the creator.

Other Support Options

Your support is much appreciated, but entirely voluntary. You may continue to make a small donation to support the project and website using Patreon. If you decide to cancel out of principal, I understand entirely. If you prefer I’ve added a PayPal button on the pledge page “Coffee” to enable you to make a small reoccurring monthly pledge that you can change or cancel it at any time.


Support the ReactorForge via PayPal



Or you can send a one-time pledge. Please include a note to let me know it’s a gift and what made you decide to support ReactorForge!




I may add members only functionality to the website linked to Patreon PayPal as well, to mirror and even enhance the capabilities Patreon offers. But I’m not sure there is indeed a need for that yet, or possibly ever. Thank you all again for your support, be it monetary, intellectual, or constructive criticism. I value all of it!

ReactorForge Parts Delivery

I just received the first shipment of parts for building more ReactorForge induction heaters, 258 pounds worth. This component is of one particular importance and one I have settled on despite other possible changes I will be making to the design. Anyone care to take a guess what part this is?

ReactorForge Induction Heater Parts Shipment ReactorForge Induction Heater Parts Shipment

Reactor Forge on the Bench

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Reactor Forge on the Bench

The Reactor Forge on the Bench and ready to hook up!

Reactor Forge on the Bench

This new rolling stand from SAMs club was perfect for holding the Reactor Forge, Bernard Weldcraft 3 gallon water cooler, extra bricks, and coils. I just need to replace the top plastic insert/mat with a piece of sheet metal. 

High-level action plan:

  • Publish existing mechanical specs, unit wiring schematic, core control board schematic, to Atmel C code to Github.
  • Add my current issues and changes that need to happen to each of the above topics in Github for proper tracking.
  • Work on those issues, changes, and improvements.
  • Make the next version, test, refine, and repeat as needed.
  • Work on BOM supply chain.
  • Kit logistics: work on which parts will be preassembled and which will require user assembly.
  • Create and publish a kit manual.
  • First test kits for users, feedback, etc. etc…

What’s next after getting the Reactor Forge on the Bench?

Hooking up cooling water and power.